Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
Machine Vision world pulppaper 89 inTroDucTion Break or event recording cameras have now been used on all types of paper board and tissue machines for over twenty years. During this time camera lighting and computer technology to capture and analyse all types of defects and break events has evolved at a rapid pace fuelled by the need for papermakers to reduce costly downtime associated with sheet breaks and compete in a market increasingly focused on high quality product. Break or event recording camera systems which are now commonly called Web Monitoring Systems or WMS have become a standard means of solving and eliminating even the most difficult paper machine runnability issues. It is estimated that there are now over 1400 WMS systems around the world with Europe and North America representing around 80 of the installed base. Over the last five years some 100 to 125 WMS systems have been sold each year and are now being used in over 30 countries. The highest concentration of WMS systems is in Northern Europe for two reasons first the initial development of this technology occurred there in the mid- nineties secondly the demand to operate machines at highest possible efficiency and production levels can often be found in Europe. Over the last decade WMS systems have become more intuitive allowing By Kari K. hilden Papertech Inc. How machine vision improves papermaking efficiency and paper quality operators to quickly and efficiently find the root cause or origin of their break causing defect or other quality issue. The cameras have become smart with full image recognition capabilities allowing them to see and alarm for any change in the sheet. In other words WMS cameras are now functioning in the same way as web inspection systems WIS located at the reel. This together with better image quality and more images per second has allowed all types of machines including small ones to justify the investment of automated camera-based web monitoring technology. Figure 1 shows some examples of WMS captured events. WeB MoniTorinG TechnoLoGY WMs PasT anD PresenT In the early nineties major advances were made in CCD charge coupled device camera technology which resulted in faster shutter speeds improved image quality and higher resolution Super VHS format analog VCRs. The outcome of such an improved break recording system was reported by a Mid-Western paper mill and demonstrated the potential that these systems offered in solving the root cause for unknown breaks. Such an automated analog VCR based event capturing system was also installed on the UPM-Kymmene it is estimated that there are now over 1400 WMs systems around the world with europe and north america representing around 80 of the installed base Figure 1. Some example events captured by high speed cameras that are going to cause or have caused a break. Most commonly problems occur in the forming and press section and in many cases are originating from poor trimming on the wire.